comparison of imrt plans with and without bone marrow sparing for the treatment of cervical cancer

Introduction: the present study aimed to compare plans with bone marrow sparing (bm-imrt) and without bone marrow sparing (n-imrt). material and methods: fifteen cases of cervical cancer cases were selected for retrospective study. all the cases were previously treated with normal imrt. for this study, plans with bm-imrt were created again for all patients following rtog guidelines. the prescribed dose of 50gy in 25 fractions was given. the plan having coverage of 95% of ptv receiving 95% of the prescribed dose was accepted. the plans were compared based on ptv coverage (dose to 2%, 98% of target); constraints of oars (organs at risk) were the volume of 40% < 40gy for normal bladder and rectum (volume receiving dose 5gy) v5<95%, v10<80%, v20<60%, v30<50% and v40<35% respectively for bone marrow and lowest possible doses to bowel were given for planning criteria. apart from this, hi, ci and r50% were also calculated concerning ptv coverage to analyze plan quality. results: there was a statistical difference in p-values of d2, d98, tv95, hi, r50% but the actual difference is less than 2%. in the case of oars, there were also significant differences in statistical as well longitudinal in values of v10, v20, v30 and v40 of bone marrow (p<0.01) and there was only statistical differences (p<0.05) at v50 of bladder and rectum. conclusion: without scarifying dose coverage for planning target volume, bone marrow can be spared while treating cervical cancer patients using imrt technique with bone marrow as an extra constraint.